Differential amplifiers have been widely used in Silicon-based circuits such as Complementary Metal Oxide Semiconductor (CMOS) field effect transistors due to their advantages in suppressing common mode signals, reducing even harmonic components, suppressing odd-mode oscillation, etc. As a representative of the 3rd generation semiconductors, GaN (Gallium Nitride) devices have advantages of high voltage, high frequency, high power density, etc., and the differential amplifiers based on the GaN devices can thus break through the power output limitations involved in the Si-based circuits.
However, the existing differential amplifiers based on the GaN devices still have disadvantages of large occupation area, high loss, low operating frequency and low power amplification efficiency.